The invention relates to light emitting diodes (i.e., LED's) and to techniques for producing integrated LED structures.
Light emitting diodes (or LED's) are devices which convert electrical energy into optical radiation. In general, these devices operate by injecting minority carriers into an active region of a semiconductor device. The active region may be the junction region of a p-n diode or it may be the i-type region of a p-i-n double heterostructure junction. When a forward bias is placed across the device, the p-type side of the junction injects holes into the active region and the n-type side of the junction injects electrons into the active region. Within the active region, the injected minority carriers (i.e., the injected holes and electrons) recombine through various mechanisms. Some of the recombinations occur through radiative transitions, others occur through nonradiative transitions. If the material that is used to form the p-n junction is an efficient luminescent material, the radiative transitions will predominate over the nonradiative transitions.
It is desirable in designing and fabricating LED's to minimize the loss mechanisms within the device which interfere with the electrical power being converted into useable light that is emitted from the device. It is also desirable to have a fabrication technique which lends itself to building integrated LED arrays on a single substrate or wafer.